I was wondering what are the pros/cons of the main types of harnesses? I have heard that 3 point are actually safer than 4 in some cases since they will allow the body to fold forward slightly around the lap belt before locking thus preventing the body from sliding underneath in certain collisions. Is this true? And are there any drawbacks to 5 point harnesses?

 

Stay away from 4-points unless you like broken ribs. A 5 or 6-point is your best bet but don't go on-track with one if you don't have rollover protection unless you like to be dead. A 5/6 point harness doesn't allow you to be pushed down in the seat by the collapsing roof. For autocrossing you will probably be ok with a 5-point because the odds of you rolling your car are slim to none.

 

none are better, there just for differant applications. most 3point harnesses are only 2' belts and as far as i know, only 3' belts are allowed @ track events. but i could be wrong. 3 point belts are good for autocross.
3 pt. harnesses don't have an anti-submarine belt. so no you can slide under them. most 4 point harnesses are just a lap belt and 2 shoulder belts. however,
u can make a 4pt with a lap belt, a y-type shoulder belt (2 shoulder belts, one attaching point) and an anti-submarine belt. asside from those weird 3pt street harness from shroth (i think)any good harness shouldn't let u lean foward. if it does, udon't have them tight enough.
now, a 5 or 6 point harness has an antisubmarine belt. with one of those an fia approved racing seat, ur not goin anywhere. u should have at least a rollbar in a car when u have harnesses just incase u go over. keep the roof of ur head.
hope some of this helps